SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd63854ce683518db7b9a1440d566ecdea40759926cf1d826d28312f25a0c083f' 
  AND token = 'YOTqngWf8UxQqo48kXB+ar/+pSBYSIluLjsfx7vmlz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}